Composite materials are commonly formed by mixing carbon materials and sometimes fibers with polymer resins to enhance the properties of a formed composite, such as improved mechanical and electrical properties. For example, carbon can serve as a reinforcement material, providing high tensile strength to the formed composite while being lightweight. In another example, carbon can be used to increase electrical conductivity in a non-conductive polymer. Carbon can be added in the form of particles or fibers, where fibers may be used to provide directional properties. The types of carbon used as filler materials in carbon-resin composites typically are carbon black, graphene, and carbon nanotubes (CNTs).
Extensive research has been performed on ways to improve the performance of polymer composite materials. Mixing techniques such as solution mixing and melt processing, with associated parameters such as types of solvents and varying viscosities, have been studied to improve the uniformity of dispersion of carbon material in the resin. Aligning carbon fibers and CNTs within a polymer melt, and the effects of alignment on resulting properties of the formed composite have also been studied. Chemical techniques to functionalize carbon have been utilized to increase bonding interaction between carbon and polymer, including the formulation of nanocomposites. Whiskerization of carbon fibers through chemical avenues, such as chemical vapor deposition, has been investigated to improve mechanical strength between fibers and resin. Research has also been performed to optimize the amounts of carbon filler to add in various formulations, as too low of an amount will not achieve the desired properties while too much tends to lead to agglomeration of the filler particles, resulting in undesirable material performance.
Making carbon-resin composites to meet desired performance parameters is a complex area, particularly in that carbon-resin composite materials are used in a wide variety of applications that can require a wide range of properties.